Equine gastric ulcer syndrome (EGUS) causes significant discomfort for horses across all breeds and disciplines. Preventing this disease plays a vital role in improving equine welfare and performance. The umbrella term EGUS covers two types of equine gastric ulcer diseases: glandular and squamous. “This distinction is based upon the location and underlying cause of these ulcers,” says Nimet Browne, DVM, MPH, Dipl. ACVIM, associate veterinarian in the department of internal medicine at Hagyard Equine Medical Institute, in Lexington, Kentucky.

Types of Equine Gastric Ulcers

Squamous ulcers, occurring in the top third of the stomach, are more common in many equine populations, such as racehorses and often attributed to excess exposure to stomach acid. “This is a management-focused disease, primarily associated with three key factors: the amount and timing of roughage, the amount of carbohydrates, and the amount and timing of exercise,” says Ben Sykes, DVM, BSc, BVMS, MS, MBA, Dipl. ACVIM, PhD, FHEA, a veterinarian and gastrointestinal disease researcher based in New South Wales, Australia.

Researchers are still working to better understand glandular ulcers, which affect the lower region of the stomach. “Risk factors for this disease are a little vaguer and, so far, a true nutritional component has not been identified,” says Browne.

“Regarding glandular disease, stress plays a much bigger role as does the horse’s individual susceptibility and the number of exercise days per week, rather than exercise quantity,” adds Sykes.

Diagnosing and Treating EGUS in Horses

If you believe your horse might have gastric ulcers, contact your veterinarian to diagnose the issue and develop a treatment and management plan. “Gastroscopy can be performed under minimal sedation and even in some cases at the farm,” says Browne. “It does involve at least eight to 12 hours of fasting to ensure an empty stomach. By using gastroscopy to identify the presence of disease, an appropriate treatment plan can be determined.”

Most horses with squamous disease return to normal with omeprazole treatment alone, she says, while only 25% of horses with glandular ulcers respond to this treatment approach. “Therefore, knowing the type of ulcers a horse has can help provide the most appropriate treatment that is tailored specifically for the individual horse,” she adds.

Understanding the differences between the two diseases can help owners and veterinarians focus their efforts where they can be most impactful. “Because squamous has a lot to do with diet, we naturally focus heavily on that for its prevention,” says Sykes. “In contrast, diet plays a much smaller, if any, role in glandular disease, so our strategies for prevention must reflect this. If we only focus on one side of the coin, then we don’t set the horse up for success in terms of total gastric health.”

A Holistic Approach to EGUS Prevention in Horses

A horse’s health and performance history, environment, and diet all contribute to his risk of developing gastric ulcers. “We must consider all these factors when designing an ulcer prevention program,” says Sykes. “This loops back to why knowing the difference between diseases and which one affects your horse—you can’t treat or prevent what you don’t know about.”

Work with your veterinarian to identify the underlying causes of stress or pain that might contribute to your horse’s gastric health “After diagnosing and treating ulcers, if progress seems halted, it is important to consider a holistic approach,” says Browne. “Performing a full orthopedic examination to identify musculoskeletal causes of pain, ensuring that the remainder of the gastrointestinal tract is healthy by addressing nutritional issues and considering herd health dynamics, is usually a good place to start.”

Keep in mind that this treatment journey might take time; each horse is unique and responds differently to treatment approaches, so you and your veterinarian might adjust your horse’s plan as needed.

Management Changes to Prevent EGUS in Horses

“Management changes continue to be the hallmark of therapy for both treatment and prevention of gastric ulcers in horses,” says Browne. Important management considerations for the prevention of squamous ulcers include forage types and availability, carbohydrate load, and exercise.

For horses with a history of squamous ulcers, the amount and timing of their forage intake is crucial. “We want our horses to ideally have unrestricted access to good-quality roughage, typically grass hay, at all times, supplemented with long-stemmed (i.e., hay, not chaff, pellets or cubes) alfalfa before exercise, says Sykes. “Where it is not possible to have unrestricted access to roughage, we want to make sure that we are feeding frequently and encouraging steady, slow consumption using strategies such as slow-feeder hay nets.”

A horse’s carbohydrate intake can also affect their risk of developing squamous ulcers. However, many recreational riding horses do not eat enough carbohydrates to significantly increase their risk, says Sykes. “Lastly, it’s exercise, specifically in the context of how much exercise at a trot or above in any given period (the ideal is five days or less each week) and timing,” he explains, with afternoon exercise preferred in most cases because this is when horses tend to naturally have the most hay in the stomach and, thus, the most natural protection.

For horses with a history of glandular ulcers, rather than focusing on total amount of exercise, owners should be attentive to the number of rest days their horse has (at least two per week is ideal) and environmental factors that could affect their stress levels. “This includes factors such as ensuring cohabitation and the opportunity to groom other horses, as well as managing human-related factors such as reducing the number of handlers or riders in sensitive horses,” says Sykes. “Behavioral modification is also important for glandular disease to reset the relationship that chronically affected horses form with the activities that we are asking of them (e.g., riding) and any pain that they might have historically experienced during such activities.”

Nutraceuticals for Preventing EGUS in Horses

“When management changes along are not sufficient, we shift towards using specific evidence-based supplements to reduce disease risk and chronic disease’s impact,” says Sykes.

A variety of nutraceutical products on the market are designed to support gastrointestinal function, but owners should be sure to choose only those with scientific backing. “Fatty acids, especially long-chain fatty acids found in fish oil (n-3 LC-PUFAs) have been shown to decrease inflammation and, in recent studies, did show a potential beneficial effect when compared to fatty acids derived from corn or flax,” says Browne. “Therefore selecting a nutraceutical derived from fish oil primarily over those with corn or flax might be beneficial.

“Pectin, which is gel-like coating agent, and lecithin, which is a phospholipid, both coat and provide a barrier against stomach acid to protect the mucosa,” she continues. Researchers have shown that licorice, aloe vera, and hyaluronan might be beneficial for preventing gastric ulcers, but more research is needed on the efficacy of these products, she adds.

Pharmaceuticals for EGUS Prevention in Horses

Veterinarians can incorporate long-term pharmaceutical management into EGUS prevention strategies at their discretion. There are many studies in which researchers have evaluated the long-term use of omeprazole along with other preventative strategies, says Browne. “The data suggests that pulse therapy in times of stress, rather than long-term use of low doses of omeprazole, would be the best usage of this medication,” she adds. However, only implement this strategy at the direction of your veterinarian and in conjunction with other long-term management strategies.

Take-Home Message

Equine gastric ulcer syndrome has a variety of risk factors associated with its development and recurrence. Therefore, taking a holistic approach to curating a prevention strategy can improve its likelihood of success. Work with your veterinarian and consider your horse’s history, environment, exercise program, and diet when developing a gastric ulcer prevention and management plan.